/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, M = 1e5+10, F = 2147483646, K = 20;
struct Edge{
int next;
ll e;
int idx;
};
int n, s, q, E, forb, tin[N], tout[N], timer = 0, dep[N];
vector<Edge> g[N];
vector<array<int, 3>> edges;
vector<bool> edg(N, 1), c(N);
bool ok;
void dfs(int v, int p, vector<ll>&dist){
if(v == E) ok = 1;
for(Edge e: g[v]){
int u = e.next;
if(e.idx == forb) continue;
if(u != p){
dist[u] = dist[v] + e.e;
dfs(u, v, dist);
}
}
}
void pre(int v, int p){
tin[v]++;
dep[v] = dep[p] + 1;
for(Edge u: g[v]){
if(u.next != p) pre(u.next, v);
}
tout[v]++;
}
bool is_ancestor(int u, int v){
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
void solve(){
cin >> n >> s >> q >> E;
for(int i = 0; i < n - 1; ++i){
int u, v, e; cin >> u >> v >> e;
Edge ee = {u, e, i + 1};
g[v].pb(ee);
ee.next = v;
g[u].pb(ee);
edges.pb({u, v, e});
}
for(int i = 1; i <= s; ++i){
int x; cin >> x;
c[x] = 1;
}
dep[E] = 0;
pre(E, 0);
if(s != n){
for(;q--;){
int i, v; cin >> i >> v;
vector<ll> dist(n+2, ll(1e15));
ok = 0;
dist[v] = 0;
forb = i;
dfs(v, 0, dist);
ll mn = 1e15;
for(int i = 1; i <= n; ++i){
if(c[i] && dist[i] < 1e15){
mn = min(mn, dist[i]);
}
}
if(ok) cout << "escaped";
else if(mn == 1e15) cout << "oo";
else cout << mn;
cout << '\n';
}
}else{
for(;q--;){
int i, v; cin >> i >> v;
int node1 = edges[i - 1][0];
int node2 = edges[i - 1][1];
if(dep[node2] > dep[node1]) swap(node1, node2);
if(is_ancestor(node1, v)) cout << 0;
else cout << "escaped";
}
}
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int T = 1, aa;
// cin >> T;aa=T;
while(T--){
// cout << "Case #" << aa-T << ": ";
solve();
cout << '\n';
}
return 0;
}
